Broderipia nitidissima G.P. Deshayes, 1863
Gibbula nivosa A. Adams, 1853
Trochus nodulatus (FOSSIL) Moore †
Trochus noduliferus J.B.P.A. Lamarck, 1822
Cantharidus nolfi G.T. Poppe, S.P. Tagaro& H. Dekker, 2006
Ueckerconulus noricus (FOSSIL) A. Nützel & Erwin, 2004 †
Rossiteria nucleolus (H.A. Pilsbry, 1903)
Rossiteria nucleus (R.A. Philippi, 1849)
Solarioconulus nudus (FOSSIL) (Münster, 1841 †)
Gibbula obesula É.A.A. Locard, 1897
Trochus obesus L.A. Reeve, 1861
Gibbula obsconica (FOSSIL) (Wood, 1842 †)
Priotrochus obscurus (W. Wood, 1828)
Priotrochus obscurus ponsonbyi (G.B. III Sowerby, 1888)
Monodonta obtusa L.W. Dillwyn, 1817
Gibbula oceanica H.A. Pilsbry, 1903
Alcyna ocellata (A. Adams, 1860)
Cantharidella ocellina (C. Hedley, 1911)
Clanculus ochroleucus (R.A. Philippi, 1853)
Trochus ochroleucus J.F. Gmelin, 1791
Leiopyrga octona (R. Tate, 1891)
Gibbula octosulcata (FOSSIL) (P. Nyst, 1835 †)
Chlorodiloma odontis (W. Wood, 1828)
Stomatella oliveri (T. Iredale, 1912)
Ethalia omphalotropis A. Adams, 1863
Cantharidus opalus (T. Martyn, 1784)
Cantharidus opalus cannoni A.W.B. Powell, 1933
Trochus oppressus (F.W. Hutton, 1878)
Lirularia optabilis (P.P. Carpenter, 1864)
Trochus optatus G.B. II Sowerby, 1838
Stomatella orbiculata A. Adams, 1850
Clanculus ormophorus A. Adams, 1854
Conotalopia ornata (G.B. III Sowerby, 1903)
Trochus ornatus (FOSSIL) Klipstein, 1843 †
Conominolia ovriensis (FOSSIL) A. Oleinik, 1991 †